In reply to papashango:
Portland and Swanage are good on the whole for microclimates. But both are rubbish when it does rain as they're mostly vertical and few routes or sectors are overhanging enough at the top to be perma dry. And the local wall is not very local if you come over the Ridgeway and can't see Portland for rain.
And on top of this. It is the first weekend of the summer holidays. Traffic may make 1.5 hrs a hopeful timescale.